The present invention relates to an electric switchgear, which can be also indicated with the equivalent terms of electric panel, or electric switchboard, or similar definitions.
The switchgear according to the present invention is particularly suitable for applications as a motor control center (MCC), preferably for medium voltage applications, i.e. for applications having a nominal voltage ranging between 1 kV and one or more tens of kV; hence, a particular reference to this application will be hereinafter made, without intending in any way to limit its possible further applications.
Medium voltage switchgear or panels are well known in the art and they usually comprise a casing that is internally divided into several compartments housing various apparatuses and equipment. For example, one compartment houses a switching unit, such as a withdrawable multi-phase contactor or circuit breaker; a second compartment houses main cables, such as bus-bars, feeding power from an electrical source; a further compartment houses a system of cables suitable to be connected to a load, typically an electric motor in case of a MCC; further, an earthing switch is usually provided for connecting to ground potential the system of cables connected to the load when the switching unit is electrically separated from the power feeding cables. Depending on the applications, switchgear may comprise other components, such as current transformers, voltage transformers, et cetera.
At present there are available on the market several types of switchgear which are required to satisfy some basic requirements, such as for example offering an excellent reliability, having a sturdy and simplified structure with an overall size as much as possible reduced, ensuring a high level of safety during working operations and maintenance interventions, et cetera.
Although known switchgear perform in a rather satisfying manner, there is still room for further improvements; for example, one usual drawback of actual switchgear resides in the fact that the main electrical components, i.e. the switching unit (be it a circuit breaker or a contactor) and the earthing switch are actuated substantially independent from each other and require dedicated manual or motor-operated actuation systems with a consequent increase of complexity of the panel, as well as manufacturing and installation costs thereof.
Therefore, it would be desirable to provide electric switchgear having an improved structure compared to known switchgear, and in particular, having an improved earthing switch with easy operation and with a reduced number of components, thereby reducing manufacturing and installation costs. The present invention is directed toward such an improved switchgear.